Systems and methods for automation of low-flow groundwater sampling

ABSTRACT

Provided are low flow groundwater fluid sampling systems and related methods of collecting fluid samples, including a low flow pump, flow cell, waste container and a communication device in communication with those components. In this manner, the low flow pump may be controlled to ensure a desired constant flow-rate is achieved, and a remote operator may monitor the status of fluid being pumped to the flow cell with the communication device, such as with a portable electronic device, including a smart phone. The system may alert the operator that fluid is ready to be collected for sampling, including at an off-site laboratory. Particularly useful applications are for monitoring groundwater quality and contamination.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/270,345, filed Feb. 7, 2019, which application claims the benefit ofand priority to U.S. Provisional Patent Application No. 62/627,400 filedFeb. 7, 2018, each of which are incorporated by reference herein intheir entireties.

BACKGROUND OF INVENTION

Current low-flow groundwater sampling techniques tend to require a humanto manually measure drawdown, evaluate stabilization of commonparameters on a water quality sonde, manually measure flow, and manuallycontrol a pump. This is a time-consuming burden on the individual,resulting in high inefficiencies, inaccurate collection protocols, andresultant decrease in sample confidence. Manual measurement and controlof the various known instruments and devices associated with groundwatersampling allows only one well to be sampled at a time per operator.There is a need in the art to reliably and cost-effectively automatemeasurement of flow and drawdown, automate control of the pump, andcombine these elements in a manner that facilitates high-throughputsample collection by a single individual for multiple samplinglocations.

SUMMARY OF THE INVENTION

The systems and methods provided herein relieve the operator of theabove challenges and provide automated or “hands-off” operation,requiring only setup. In fully automated employment, all that may berequired is for the operator to collect a ready to transport sample uponalert that the sample is ready to be collected. The systems and methodsdescribed herein facilitate time-, labor-, and cost-efficiencies tosample and perform real-time monitoring at multiple sites, such asgeographically separated wells, simultaneously. This results in atremendous savings of effort and time. The systems and methods describedand claimed herein further provide the ability to efficiently monitorgroundwater contamination by at least partially automating the fluidcollection process. Before fluids can be collected for subsequentanalysis, including at an off-site lab having the ability to preciselyquantify a range of chemical species, ranging from volatile organiccompounds to inorganic metals, the fluid must be “clean”. In particular,the fluid in the well should be purged in order to obtain an accuratemeasure of groundwater contamination and avoid measuring initial fluidsthat tend to build-up and store contaminants so that a reading of thosesamples is not a true indication of environmental groundwatercontamination level. The systems and methods provided herein automatethis procedure so that an operator need not be on-site adjusting pumpflow-rate, calculating water parameters, and deciding when stabilizationis achieved. Instead, the operator may be alerted, such as via awireless communication to a hand-held device on the person of theoperator, that sample stabilization is achieved and fluid (e.g., water)collection may begin. In this manner, significant time savings andefficiencies are achieved, even while reducing the likelihood of errorscaused by operator error, including arising from tracking many waterquality parameters over time to determine when sampling may occur. Thesystems and methods similarly free the operator from being tied tospecific testing sites for specific times, thereby further increasingflexibility and efficiency.

The systems and methods may be incorporated with a wireless networkenabled device (also generally referred herein is a communication devicecapable of receiving data from any one or more components of thesystem), thereby providing a convenient platform for remotely reviewingflow-rate, drawdown, pump status, and any other parameters of interest.Accordingly, any of the low flow pumps may be a Bluetooth enabled pump,for instance, thereby facilitating wireless communication and control.

The systems and methods may be used with any of a range of water qualitysondes, including any of the sensors and/or multiparameter sondesdescribed in U.S. Pat. Nos. 9,689,855 (describing multiparametersondes), 9,835,554 (describing conductivity sensors), 9,778,180(describing turbidity sensors as part of the flow cell), each of whichare incorporated by reference in their entirety to the extent notinconsistent herewith.

Any of the systems and methods may incorporate auto-calibration of thesensors, run stabilization routines, and sample auto-collection.Notification may be automatically sent as an alert that the samples areready for pickup and/or waste water is ready to be disposed of. A mobileapp may interface with the water quality sonde (e.g., sensors) toautomatically calculate stabilization and collect other pieces ofinformation.

Provided herein are low flow groundwater fluid sampling systems. Thesystem may comprise: a low flow pump; a flow cell in fluid and/orelectronic communication with the low flow pump, wherein the flow cellcomprises one or more fluid quality sensors; a waste container in fluidcommunication with the flow cell for collecting a waste fluid, whereinthe waste container comprises a level sensor for measuring a waste fluiddepth in the waste container; a communication device in wirelesscommunication with each of the pump, flow cell and waste container,wherein the low flow pump has an adjustable pump power to provide adesired constant flow-rate to the flow cell from the electroniccommunication between the low flow pump and the level sensor and the atleast one fluid quality sensor measures one or more fluid parametersover a time course to assess fluid stabilization status; upon fluidstabilization the communication device indicates an affirmative fluidstabilization condition and that a fluid sample may be collected; andall fluid provided to the flow cell by the low flow pump is eithercollected in a fluid sample or directed to the waste container andcollected as the waste fluid.

The systems provided herein are compatible with any of a range of flowsensors incorporated or positioned anywhere in the system, so long as aflow-rate can be determined and used to control pump power so as tomaintain a desired flow-rate through the system. For example, the wastecontainer level sensor itself can be used as a type of flow sensor,wherein the change in volume of waste fluid as a function of timeprovides a measure of flow-rate for controlling the adjustable pumppower. Similarly, a separate flow sensor may be used upstream from theflow cell, downstream from the flow cell, or within the flow cell, toprovide a measure of flow-rate used to control or adjust pump power, soas to maintain a desired, substantially constant, flow-rate.

Accordingly, any of the systems may further comprise a flow sensor influid and electronic communication with the low flow pump.

The system may further comprise an autosampler in fluid communicationwith the flow cell, wherein an output flow from the flow cell for anaffirmative fluid stabilization condition is directed to the autosamplerfor collection. In this manner, an operator need not be physicallyon-site in order to collect a fluid sample. Instead, an operator orother individual, when convenient, can go to the site and pick-up thesamples from the collector for subsequent off-site transport.

The flow cell may comprise a multi-parameter sonde having a plurality offluid quality sensors. In this manner, a plurality of fluid parametersmay be monitored, thereby providing improved liquid assessment fidelityand assurance that an affirmative fluid stabilization condition isreached. Fluid quality sensors include any one or more selected from thegroup consisting of: a turbidity sensor, a pressure sensor, atemperature sensor, an electrical conductivity sensor, a pH sensor, anelectrochemical sensor such as an oxidation reduction potential (ORP)sensor, a fluorescence sensor, and any combination thereof.

Any of the systems may further comprise a depth sensor for assessingfluid draw-down level in a monitoring well, wherein the depth sensor is:in wireless communication with the communication device; electroniccommunication with the pump; or in communication with both.

Any of the flow cells provided herein may further comprise anauto-calibrator for automatically calibrating the one or more fluidquality sensors. For example, the auto-calibrator may have calibratedsolutions with a known fluid parameter magnitude, including differentsolutions spanning a range of fluid parameter magnitudes, with automatedintroduction of calibration solutions to provide a type of calibrationcurve to calibrate the sensor over a range of values prior tointroduction/of groundwater. Alternatively, the flow cell may becalibrated before being used in any of the processes described herein.Accordingly, for a collected fluid sample, a wide range of fluid qualityparameters may be reliably measured for the fluid sample.

The systems and methods provided herein are compatible with a range offlow-rates, depending on the application of interest, such as relatedflow characteristics in and around a test well. For example, the desiredor constant flow-rate may be greater than or equal to 1 mL/min and lessthan or equal to 500 mL/min.

The waste container level sensor may comprise a pressure transducer at abottom surface of the waste container to measure waste fluid level inthe waste container. Other examples include optical-type sensors thatoptically measure a path length or change in an optical property,thereby detecting fluid level. With a waste fluid height detected, thevolume is determined for a known cross-sectional area of the wastecontainer. A mass sensor may be used to measure the mass of liquidprovided to the waste container, so that for a known liquid density,flow-rate is readily determined.

In any of the systems provided herein, one or more of a fluid flow-rateor a water well depth is transmitted to the communication device and acontrol signal is transmitted from the communication device to the lowflow pump to maintain the desired or constant fluid flow-rate and/or awater well depth.

In any of the systems provided herein, a measured waste fluid depth maybe wirelessly transmitted to the communication device. The communicationdevice may then provide an alert to a user, such as a waste fluid alarmfor a waste fluid depth that is greater than or equal to a waste fluiddepth maximum. In this manner, overfilling of the waste fluid containeris avoided. The waste fluid depth maximum may be less than the depth ofthe waste container, so as to provide time to an operator before thecontainer overfills and to provide the ability to handle the wastecontainer without spilling. For example, the waste fluid depth maximummay correspond to about 75% to 100% of the waste container depth, suchas between 75% and 95%, and any sub-ranges thereof.

The communication device may comprises a mobile smartphone, a handheldportable device, or a computer.

The communication device may comprise a telemetry system positioned fortransmitting data to a mobile device or a remote monitoring station.

The systems provided herein can be part of a multiplexed systemcomprising a plurality of the low flow groundwater sampling systems forsimultaneously monitoring of a plurality groundwater wells. In thismanner, one operator may manage and monitor fluid collectionsubstantially simultaneously over a wide geographic range.

The systems provided herein are compatible with a range of applications,including for use in a groundwater contamination application, wherein aclean fluid sample is used for off-site testing of said clean fluidsample. Clean refers to a sample that has been appropriately validatedas being in an affirmative fluid stabilization condition, as determinedby the sensors in the flow-cell.

The groundwater contamination application may further comprisemonitoring oil or gas, or byproducts thereof, for groundwatercontamination.

Also provided herein are methods for collecting fluid samples using anyof the systems described herein.

For example, a method for collecting low flow fluid samples fromgroundwater may comprise the steps of: continuously pumping a flow ofgroundwater fluid to a flow cell at a substantially constant flow-rate;measuring a fluid quality parameter time course with a fluid sensor insaid flow cell; identifying a positive fluid quality stabilizationstatus for said measured fluid quality parameter that reaches asteady-state value; and wirelessly transmitting a signal to acommunication device indicating a fluid sample is ready to be collectedfrom said flow of groundwater fluid.

The method may further comprise the step of manually collecting thefluid sample after the fluid stabilization is achieved.

The method may further comprise the steps of collecting a waste fluidthat exits said flow cell in a waste container; and monitoring a wastefluid level with a level sensor connected to the waste container.

Any of the methods may be used with an autosampler, such as byactivating an autosampler to automatically collect fluid sample thatexits the flow cell after the positive or affirmative fluid qualitystabilization status is identified.

The method may be used for simultaneous collection of a plurality of lowflow fluid samples from a plurality of wells, such as by a multiplexedconnection of a plurality of the systems described herein, with onesystem provided per well.

The continuously pumping may be by a low-flow pump fluidly connected orin fluid contact with a sample well.

The sample well may be configured to monitor contamination of groundwater, including oil or gas contamination, heavy metal contamination,solvent contamination, or contamination of a material from an industrialprocess.

Any of the methods may further comprise the step of auto-calibrating thefluid sensor before the measuring step by: flushing the flow cell with aclean fluid, such as water; filling the flow cell with a calibrationsolution; measuring a calibration fluid quality parameter with the fluidsensor until stability is reached; calculating a new calibrationcoefficient for the fluid sensor; storing the new calibrationcoefficient for a subsequent fluid test measurement; and repeating untilall water quality parameters for all fluid sensors are calibrated.

The continuously pumping may be automated or semi-automated by measuringfluid flow through said flow cell and/or measuring a fluid depth in asample well, wherein the measured fluid flow and/or fluid depthgenerates an output that is provided as an input to said low flow pumpto control pump power, thereby controlling fluid flow in a feedback loopso as to maintain constant flow-rate and/or fluid depth in said samplewell.

Provided herein are various low flow groundwater fluid sampling systems,including those comprising: a low flow pump; a flow cell in fluidic andelectronic communication with said low flow pump, wherein said flow cellcomprises one or more fluid quality sensors; a waste container in fluidcommunication with said flow cell for collecting a waste fluid, whereinsaid waste container comprises a level sensor for measuring a wastefluid depth in said waste container; an autosampler in fluidcommunication with said flow cell, wherein an output flow from said flowcell for said affirmative fluid stabilization condition is directed tosaid autosampler for collection, wherein: a communication device is incommunication, including wireless communication, with each of said pump,flow cell and waste container; said pump has an adjustable pump power toprovide a desired constant flow-rate to said flow cell from saidelectronic communication between said low flow pump and said flow sensorand said at least one fluid quality sensor measures at least one or morefluid parameters over a time course to assess fluid stabilizationstatus; upon fluid stabilization said communication device actuates saidautosampler to collect a fluid sample; all fluid provided to said flowcell is either collected in a fluid sample or directed to said wastecontainer and collected as said waste fluid; and said communicationdevice is configured to generate a sample ready signal to a user oroperator upon collection of said fluid sample. In this manner, all thatis required of the user or operator is to collect the fluid sample fortransport to an off-site testing facility.

Any of the systems may comprise a sampling controller for implementingany of the control schemes described herein. For example, the samplingcontroller may be part of, or operably connected to, the communicationdevice.

Also provided are systems for sampling or monitoring groundwater,optionally under low-flow conditions, the system comprising: a flow cellincluding at least one fluid quality sensor; a pump in flowcommunication with the flow cell; a flow sensor in flow communicationwith the flow cell; a pump controller for regulating a fluid flow-ratefrom a groundwater source to the flow cell, the pump controlleroperatively coupled to the pump; and a sampling controller forimplementing a control scheme for the groundwater sampling system, thesampling controller communicatively coupled to: the flow sensor, the atleast one fluid quality sensor, and the pump controller. The controlscheme may include: (a) transmitting a control signal to the pumpcontroller in response to signals received from the flow sensor tofacilitate maintaining a substantially constant fluid flow-rate from thegroundwater source to the flow cell; (b) determining one or more fluidparameters over a time course based on signals received from the atleast one fluid quality sensor; (c) determining a fluid stabilizationstatus of groundwater flowed to the flow cell by the pump based on theone or more fluid parameters determined in (b); and (d) in response toan affirmative fluid stabilization condition being determined in (c),initiating collection of at least one fluid sample of the groundwaterunder test. As described, the collection may be into a sample containerfor subsequent transport and testing in an off-site testing facility.The collection may be automated or manual.

Any of the systems described herein optionally include a waste containerin flow communication with the flow cell, wherein the flow sensor is adepth sensor positioned in the waste container configured to measure theamount of waste fluid collected in the waste container. In this manner,the flow-rate is determined by the change in the volume of waste fluidwith time, thereby avoiding a need for a separate flow sensor. Ofcourse, any of the systems and methods described herein are compatiblewith one or more flow sensors positioned at distinct locations, such asupstream and/or downstream of the flow cell, or within the flow cellitself, to provide additional monitoring capability, quality control andtroubleshooting. Similarly, any one or more additional flow componentsmay be utilized, such as filters, pressure sensors, valves, and thelike. A filter is optionally utilized near an inlet to the system, tofurther minimize risk of clogging and fouling.

The flow sensor may be positioned upstream of an inlet of the flow cell;the fluid flow-rate from the groundwater source to the flow cell is afirst fluid flow-rate of the groundwater under test into the inlet; thesystem may further comprise an outlet flow sensor for measuring a secondflow-rate of the groundwater under test out of an outlet of the flowcell, the outlet flow sensor positioned proximal the outlet andcommunicatively coupled to the sampling controller; and the controlscheme further includes: (e) comparing a measured value of the secondflow-rate to a measured value of the first flow-rate to determine adifference therebetween.

The system may further comprise a waste container in flow communicationwith the flow cell for collecting a waste fluid; a first valvepositioned upstream of the inlet and in flow communication with thepump, the flow cell, and the waste container; and a first valvecontroller for alternately directing flow of groundwater from thegroundwater source to one of at least two flow paths, the first valvecontroller operatively coupled to the first valve, the at least two flowpaths including: a first flow path from the pump to the flow cell, and asecond flow path from the pump to the waste container.

The control scheme may further include: (f) in response to a value ofthe difference determined in (e) being greater than or equal to apredetermined flow-rate difference, transmitting a control signal to thefirst valve controller to facilitate diverting the flow of groundwaterfrom the pump to the second flow path.

The system may further comprise: a second valve positioned downstream ofthe outlet and in flow communication with the flow cell and the wastecontainer; and a second valve controller for alternately opening andclosing the second valve to facilitate alternately starting andstopping, respectively, flow of groundwater into or out of the outlet,the second valve controller operatively coupled to the second valve.

The control scheme may further include: (g) in response to a value ofthe difference determined in (e) being greater than or equal to apredetermined flow-rate difference, transmitting a control signal to thesecond valve controller to facilitate closing the second valve andstopping flow of groundwater into the outlet.

The system may further comprise: a waste container in flow communicationwith the flow cell for collecting a waste fluid; a second valvepositioned downstream of the outlet and in flow communication with theflow cell and the waste container; and a second valve controller foralternately directing flow of groundwater from the flow cell to one ofat least two flow paths, the second valve controller operatively coupledto the second valve, the at least two flow paths including: a first flowpath from the flow cell to the at least one fluid sample, and a secondflow path from the flow cell to the waste container.

The control scheme may further include: (i) transmitting a controlsignal to the second valve controller to facilitate diverting thegroundwater under test to the first flow path to further facilitatecollecting the at least one fluid sample.

Any of the systems may further comprise an autosampler for collecting aplurality of fluid samples, the autosampler including: a sampleplatform, and an electric motor operatively coupled to the sampleplatform, and a motor controller operatively coupled to the motor, themotor controller communicatively coupled to the sampling controller, andwherein, for (d), with the control scheme further including: (i) for atleast one iteration: transmitting a control signal to the motorcontroller to facilitate incrementally moving the sample platform from aposition of a first container for containing a first fluid sample to atleast a second container for containing at least a second fluid sample.

The at least one of: the flow sensor, the at least one fluid qualitysensor, and the pump controller, may be wirelessly communicativelycoupled to the sampling controller.

The at least one fluid quality sensor may include at least one of: aturbidity sensor, a pressure sensor, a temperature sensor, a dissolvedoxygen sensor, an oxidation reduction potential sensor, and afluorescence sensor.

The sampling controller may comprise a computing device, the computingdevice including: a processor, and memory communicatively coupled to theprocessor;

and the computing device implements the control scheme for the system.

The memory device may include a non-transitory computer readable mediumstoring processor-executable instructions encoded as software, which,when executed by the processor, cause the processor to implement thecontrol scheme for the system.

The flow sensor, the at least one fluid quality sensor, and the pumpcontroller, may be wirelessly communicatively coupled to the computingdevice.

The computing device may be a mobile device, such as a smartphone; andthe software includes a smartphone app. In this manner, an operator maybe untethered to a specific location, and can conveniently move aboutthe day, wherein in conventional systems, substantial time was devotedto being onsite to control the process and ensure appropriate sampleswere collected.

Any of the systems and methods may comprise an autosampler, such as anautosampler having: a sample platform, and an electric motor operativelycoupled to the sample platform, and a motor controller operativelycoupled to the motor, the motor controller communicatively coupled tothe sampling controller. The control scheme may further include: for atleast one iteration: transmitting a control signal to the motorcontroller to facilitate incrementally moving the sample platform from aposition of a first container for containing a first fluid sample to atleast a second container for containing at least a second fluid sample.In this manner, fluid samples may be periodically collected and readyfor pick-up and transport to a testing facility.

Also provided is a method for monitoring groundwater comprising: (A)flowing, by a pump operatively coupled to a pump controller, groundwaterunder test from a groundwater source to a flow cell in flowcommunication with the pump, the flow cell including at least one fluidquality sensor; (B) collecting at least one fluid sample of thegroundwater under test from an output flow of the flow cell; and (C)controlling, by a sampling controller, the pump controller to facilitateregulating a fluid flow-rate from a groundwater source to the flow cell,wherein the sampling controller is communicatively coupled the pumpcontroller and communicatively coupled to a flow sensor positionedupstream of the flow cell and positioned downstream of the pump, thecontrolling step comprising: (i) transmitting, by the samplingcontroller, a control signal to a pump controller in response to signalsreceived from the flow sensor to facilitate maintaining a substantiallyconstant fluid flow-rate from the groundwater source to the flow cell;(ii) determining one or more fluid parameters of the groundwater undertest over a time course based on signals received from the at least onefluid quality sensor; (iii) determining a fluid stabilization status ofthe groundwater under test based on the one or more fluid stabilizationparameters determined in (ii); and (iv) in response to an affirmativefluid stabilization condition being determined in (iii), initiatingcollections of at least one fluid sample of the groundwater under test.

The flow sensor may be a first flow sensor positioned upstream of aninlet of the flow cell; the fluid flow-rate from the groundwater sourceto the flow cell is a first fluid flow-rate of the groundwater undertest into the inlet; wherein the system further comprises an outlet flowsensor for measuring a second flow-rate of the groundwater under testout of an outlet of the flow cell, the outlet flow sensor positioneddownstream of the first flow sensor and proximal the outlet, the outletflow sensor communicatively coupled to the sampling controller; and thecontrolling step further comprises: (v) receiving signals from theoutlet flow sensor for measuring a second flow-rate of the groundwaterunder test out of an outlet of the flow cell; and (vi) comparing ameasured value of the second flow-rate to a measured value of the firstflow-rate to determine a difference therebetween.

The controlling step may further comprise: (vii) in response to a valueof the difference determined in (vi) being greater than or equal to apredetermined flow-rate difference, transmitting a control signal to thepump controller to facilitate at least one of: stopping operation ofpump, decreasing the first flow-rate.

The controlling step may further comprise: (v) receiving signals from awaste container sensor for measuring a waste fluid depth of a wastecontainer in flow communication with the flow cell for collecting awaste fluid, wherein the waste container sensor is positioned in thewaste container, and wherein the waste container sensor iscommunicatively coupled to the sampling controller; (vi) determining avalue of the waste fluid depth based on the signals received from thewaste container sensor; and (vii) in response to the waste fluid depthvalue determined in (vi) being greater than or equal to a predeterminedwaste depth value, at least one of: a) transmitting a control signal tothe pump controller to facilitate stopping operation of pump ordecreasing the fluid flow-rate; and b) providing an alarm.

The collecting step may further include collecting a plurality of fluidsamples of the groundwater under test using an autosampler.

Also provided herein are systems for performing any of the methodsdescribed herein.

Also provided herein is a non-transitory computer readable mediumstoring processor-executable instructions for implementing a controlscheme of a groundwater sampling or monitoring system, which, whenexecuted by a processor of the groundwater sampling or monitoringsystem, cause the processor to: flow, by a pump operatively coupled to apump controller, groundwater under test from a groundwater source to aflow cell including at least one fluid quality sensor, wherein the pumpcontroller, the at least one fluid quality sensor, and a flow sensorpositioned upstream of the flow cell and downstream of the pump arecommunicatively coupled to the processor; collect at least one fluidsample of the groundwater under test from an output flow of the flowcell; and control the pump controller to facilitate regulating a fluidflow-rate from the groundwater source to the flow cell, wherein, whenexecuted by the processor to control the pump controller, theprocessor-executable instructions further cause the processor to: (i)transmit a control signal to a pump controller in response to signalsreceived from the flow sensor to facilitate maintaining a desired orconstant fluid flow-rate from the groundwater source to the flow cell;(ii) determine one or more fluid parameters over a time course based onsignals received from the at least one fluid quality sensor; (iii)determine a fluid stabilization status of groundwater flowed to the flowcell by the pump based on the one or more fluid stabilization parametersdetermined in (ii); and (iv) in response to an affirmative fluidstabilization condition being determined in (iii), initiate collectionof at least one fluid sample of the groundwater under test.

Without wishing to be bound by any particular theory, there may bediscussion herein of beliefs or understandings of underlying principlesrelating to the devices and methods disclosed herein. It is recognizedthat regardless of the ultimate correctness of any mechanisticexplanation or hypothesis, an embodiment of the invention cannonetheless be operative and useful.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a low flow groundwater fluidsampling system.

FIG. 2 is a schematic illustration of a low flow groundwater fluidsampling system with a mobile device as a communication device.

FIG. 3 is a schematic illustration of a low flow groundwater fluidsampling system with autosampler and telemetry.

FIG. 4 is a flow chart illustration of a method for collecting fluidsamples from groundwater.

FIG. 5 is a flow chart illustration of a method for collecting fluidsamples from groundwater according to another embodiment.

FIG. 6 is a schematic illustration of a groundwater sampling systemaccording to another embodiment.

FIG. 7 is state diagram illustration of a control scheme for groundwatersampling.

FIG. 8 is a plot illustrating an example of a fluid stabilizationcondition.

FIG. 9 is a schematic illustration of an autosampler.

FIG. 10 is a schematic illustration of a networked computing environmentfor implementing any of the disclosed systems and methods forgroundwater sampling.

DETAILED DESCRIPTION OF THE INVENTION

In general, the terms and phrases used herein have their art-recognizedmeaning, which can be found by reference to standard texts, journalreferences and contexts known to those skilled in the art. The followingdefinitions are provided to clarify their specific use in the context ofthe invention.

“Low flow groundwater” refers to water samples that reflect total mobileorganic and inorganic loads that are transported through the subsurfaceunder ambient flow conditions. Typical applications herein that rely onlow flow groundwater are monitoring wells that are drilled for thepurpose of monitoring contamination, including contaminants associatedwith the oil and gas industry or, more generally, any chemicalmanufacturing or processing application. Accordingly, the monitoringwell may be anywhere oil and gas is commercially present, includingproduction sites, storage sites, gas stations, transportation (e.g.,pipelines), manufacturing, refining, and the like. Of course, thesystems and methods provided herein are versatile, and may beincorporated and located for any of a range of applications where fluid(liquid) sampling is desired for subsequent off-site analysis, such asin a testing facility having instrumentation, sensitivity and/orcost-efficiency not readily available in the field.

“Low flow pump” is used broadly to refer to pumps that are designed toprovide relatively low flow-rates, such as less than 1 L/min, or between1 mL/min to 500 mL/min. The actual flow-rate range is selected so as toensure there is minimal disturbance of the well to minimize unwantedparticulate mixing with the water that has naturally flowed to themonitoring well, resulting in unwanted effects including on turbiditymeasurement. In addition, the low flow-rates maintain low water-leveldrawdowns. A low and steady flow-rate generated by the low-flow pumpallows for monitoring of water parameters in order to determine whensampling may begin. Any of a range of pumps, such as adjustable rate,peristaltic, submersible, centrifugal, bladder and the like may be used.The pump may be placed downhole and configured to be submersed in water.Alternatively, the pump may be placed out of the water, with tubingprovided between the water and pump for steady withdrawal of water. Thepump may be adjusted to ensure there is minimal water level drawdown inthe well, such as less than about 0.3 feet, or a draw down level thatremains constant or substantially constant.

The samples that are properly collected are suitable for analysis ofgroundwater contaminants such as volatile and semi-volatile organicanalytes, dissolved gases, pesticides, PCBs, metals, other inorganics ofinterest or naturally occurring analytes. The collected samples may betransported to a testing facility for precise testing of any one or morematerials, including to assess groundwater contamination. Preferably thepump is made of a material, or has a coating, so that there is minimalleaching for pumps that are submersed in the water, thereby minimizingrisk of unwanted self-contamination.

“Desired constant flow-rate” refers to a user-determined flow-rate thatwill result in good purging and subsequent suitable fluid for collectionand subsequent sampling. Preferably, the desired constant flow-rate isselected so that there is not an undue fluid drawdown from the well andthat the natural inflow of water balances the fluid pumped out of thewell. Typical flow-rate values are less than 1 L/min, such as between 1mL/min and 500 mL/min. Accordingly, the desired constant flow-rate maybe greater than or equal to 1 mL/min and less than or equal to 500mL/min, or any subranges thereof. “Constant”, in this context, is usedbroadly and refers to the goal that flow-rate remains relatively steady,recognizing it is not practical, especially in the field, to achieve anexact non-deviating constant. Instead, practical realities such asrelated to fluid level fluctuations, pump power fluctuations,obstructions, disturbances and any of a variety of other externalfactors, will result in some deviation from constant. Accordingly,desired constant flow-rate may refer to a time-averaged flow-rate with astandard deviation or, more simply a maximum deviation, that is within20%, 10% or 5% of the mean or desired flow-rate. If the measuredflow-rate then falls outside such a standard deviation or has a maximumdeviation outside of 20%, 10% or 5%, the flow may be considered notconstant, and the system continues to pump until a sufficient durationof a desired constant flow-rate is achieved. That duration may beselected as greater than or equal to 1 minute, 5 minutes, 15 minutes, 30minutes, or 1 hour. In this aspect, “constant flow-rate” may be usedinterchangeably with “substantially constant flow-rate” to reflect thereis some tolerance in sample collection to minor variations in flow-rate,such as a mean flow-rate with a standard deviation that is within 20%,10% or 5% of the mean flow-rate or a maximum deviation that is within20%, 10% or 5% of the mean or desired flow-rate.

The “flow cell” directs pumped fluid over one or more “fluid qualitysensors”. As discussed, any one or more of the sensors or sondes,including a multiparameter sonde, of U.S. application Ser. No.16/251,651 (“Fast Response Temperature Sensors” filed Jan. 18, 2019,Atty Ref. 337310: 90-17 US), U.S. Pub. Nos. 2017/0176183, 2016/0146777;and U.S. Pat. Nos. 9,689,855; 9,778,180, D755,655, are incorporated byreference, including for use in flow cells or any other position where aliquid parameter is desirably measured. See also, In-Situ, Inc. “Lowflow kits and accessories” available atin-situ.com/wp-content/uploads/2014/11/LowFlow_Kits_2017.pdf (November2015), for exemplary low-flow kits, components and accessories.

“Steady-state” or “stabilization” refers to one or more fluid qualitysensors achieving a stable read-out of the one or more water qualityparameters. Examples of fluid quality sensors include turbidity,temperature, specific conductance, pH, oxidation-reduction potential(ORP), and dissolved oxygen (DO). Stabilization can be defined by a useror may be a rule or regulation implemented by a government agency orstandard setting body, and generally refers to multiple consecutivemeasurements that have a substantially constant measured water qualityparameter. The invention is compatible with any number or types ofstabilization definitions. For example, stabilization may refer to adeviation, such as maximum deviation, standard deviation, or the like,over a number of consecutive measurements or a time frame, such as threeor more consecutive measurements or a time period that is greater than auser-specified amount. The specific definition of stabilization can befrom a regulation, such as US EPA EQASOP-GW4 “Low stress (low flow)purging and sampling procedure for the collection of groundwater samplesfrom monitoring wells” Rev. 4 Sep. 19, 2017 (EPA 2017). For example:“Stabilization is considered to be achieved when three consecutivereadings are within the following limits: Turbidity (10% for valuesgreater than 5 NTU; if three Turbidity values are less than 5 NTU,consider the values as stabilized), Dissolved Oxygen (10% for valuesgreater than 0.5 mg/L, if three Dissolved; Oxygen values are less than0.5 mg/L, consider the values as stabilized), Specific Conductance (3%),Temperature (3%), pH (±0.1 unit), Oxidation/Reduction Potential (±10millivolts).” EPA 2017 is specifically incorporated by reference herein,including for the various definitions of “stability” for the differentliquid quality parameters.

Whether the measurement has achieved “stability” or is “stable” depends,at least in part, on the sensitivity, reliability and reproducibility ofthe underlying sensor, as well as the particular application andcorresponding liquid quality characteristics. For example, fluids havinghigh turbidity may have a higher variability in measurements than lowerturbidity. Stability may be considered achieved for turbidity variationof less than 10%, dissolved oxygen of less than 10%, specificconductance of less than 3%, temperature of less than 3%, pH variationof less than 0.1, and/or ORP variation of less than 10 mV. The variationmay be calculated for three or more consecutive readings, includingreadings that are separated by at least one full fluid volume turnoverof the flow cell.

“Communication device” is used broadly herein to refer to a component ordevice that is capable of receiving and/or transmitting signals.Accordingly, a communication device can be a type of controller, adisplay, a computer or processer that receives signals, processes them,and sends commands, such as pump power command, valve control, sampling,collection, waste level action, and the like. The communication devicecan comprise a portable device or a work station, including that isbeing used by the operator to monitor the systems and, as appropriate,collect samples or over-ride the system.

“Operably connected” or “operatively coupled” refers to a configurationof elements, wherein an action or reaction of one element affectsanother element, but in a manner that preserves each element'sfunctionality. For example, any of the controllers provided herein maybe described as being operatively coupled to another component whosesignal is used to control at least a portion of the system, such as pumppower, flow direction, sample collection, or a signal sent to, orreceived by, an operator or an electronic device used by an operator.

“Fluid communication” refers to components that are connected by fluidflow, but in a manner that does not affect either component'sfunctionality. The connection may be direct, where a flow from an outputof one component is provided as an input to another component. Theconnection may be indirect, where an intervening component is positionedbetween the components.

EXAMPLE 1: LOW-FLOW GROUNDWATER SAMPLING SYSTEM

FIGS. 1-3 are schematic overviews of a system for automation of low-flowgroundwater fluid sampling. Low flow pump 10 pumps fluid 200, such asgroundwater that has entered and been collected in a well 130 asindicated by arrows 201, to a flow cell 20. The system optionallyincludes a separate flow sensor 30. Well 130 may be a monitoring wellfor monitoring possible contamination of groundwater. The flow cell 20is in fluid and electronic communication with the low flow pump 10. Inthis manner, the measured parameters by the flow cell may be used to, inturn, control pump, thereby establishing a feedback control. The flowcell 20 may have one or more fluid quality sensors 40 for measuring oneor more fluid parameters. The flow cell may have an inlet port 22 fordelivering fluid to the flow cell and outlet port 24 for removal offluid from the flow cell. Valves 26 may be used to control flow of fluidto either waste container 50 or to fluid sample container 80, includinga fluid sample container that is part of an autosampler 100 forautomatically collecting samples for later pick up by an operator fortransport to an off-site testing facility. A level sensor 60 may bepositioned at a bottom surface 150 of the waste container 50 to providean indication of the level of waste fluid 90 in the waste container. Anyof the level sensors may use a pressure sensor to determine fluid heightby P=ρgh (P is pressure, ρ is density, g is acceleration due to gravity,and h is fluid height). Furthermore, by measuring the change in thewaste fluid level with time, the level sensor may itself becharacterized as a flow sensor, where a plot of height versus time andthe corresponding slope provides a measure of flow-rate, with adjustmentto pump power made to maintain a relatively constant slope.

Communication device 70 is in wireless communication with many of thecomponents, as illustrated by dashed arrows. As shown in FIGS. 2 and 3,communication device 70 may include a mobile device 75 and/or atelemetry system 77. The arrows are two-ended to reflect that not onlyis data provided to the device, but the device may be used to controlthe system, including pump flow-rate, sensor status, and any othercomponent of interest, including valve 26 direction.

With respect to the well 130, a depth sensor 110 may be used to providea measure of fluid depth in the well, thereby providing informationabout fluid drawdown level 120. The depth sensor 110 may be a pressuresensor. Sensor 110 may be in wireless communication with device 70and/or pump 10, so that pump power or fluid flow-rate is adjusted so asto maintain an appropriate fluid depth, and maintain drawdown 120 at anacceptable level, or at least a constant level.

An “auto-calibrator” 140 may be incorporated into the system forautomatically calibrating the sensors. The auto-calibrator may beprovided as an adaptor that fluidically connects to the flow cell, suchas via a controllable valve. One or more calibration solutions may beconnected so that the calibration solution(s) are forced, including viaa pump, into the cell and flushed out. The pumping force may be via theconnected low flow pump or by a separate auto-calibrator pump. Wastesolutions go to the waste bucket.

The flow cell 20 may be installed at an orientation angle that is notvertical (as shown in FIG. 1) and/or that is not horizontal, to preventbubbles from forming on the sensor head. In another example (not shownin FIG. 1), the flow cell 20 may be installed at any orientation anglethat is suitable for functioning according to design specifications inthe system for automation of low-flow groundwater fluid sampling. Theflow cell 20 has minimal volume within the cell, to allow for fasterflow cell turnover and to minimize the volume of calibration solutionsused, with an inlet port and an outlet port. The flow cell may becharacterized as having an internal volume corresponding to the volumeof liquid within the flow cell. The invention is compatible with a rangeof flow cell internal volumes, such as between 0.1 mL and 1 L, between40 mL and 500 mL, and any sub-ranges thereof, with a preference forvolumes as low as possible to provide faster flow cell turnover andefficiently utilize calibration solutions for the sensors.

The waste container may comprise a bucket with a level sensor orpressure transducer at or near the bucket bottom. The waste container isconfigured to allow waste flow to drop into the bucket with minimalsurface disruption for more accurate readings. The bucket may have aconstant diameter so that the pressure transducer is reliably calibratedto send a warning as to the need to empty the container of waste fluidand/or to decrease the flow through or stop the pump to avoid overflowof waste fluid. A top cover may be connected to the container to preventspillage.

FIG. 4 is a method 300 for collecting low flow fluid samples fromgroundwater. In an example, method 300 is implemented and/or performed,at least in part, using the systems shown and described with referenceto FIGS. 1-3. Method 300 includes continuously pumping 303 a flow ofgroundwater fluid to a flow cell at a substantially constant flow-rate.Method 300 includes measuring 305 a fluid quality parameter time coursewith a fluid sensor in said flow cell. Method 300 includes identifying307 a positive fluid quality stabilization status for the measured fluidquality parameter that reaches a steady-state value. Method 300 includeswirelessly transmitting 309 a signal to a communication deviceindicating a fluid sample is ready to be collected from said flow ofgroundwater fluid. In an example, method 300 includes manuallycollecting 311 the fluid sample.

In an example, method 300 includes collecting 313 waste fluid that exitssaid flow cell in a waste container, and monitoring 315 a waste fluidlevel with a level sensor connected to said waste container. In theexample, method 300 optionally includes activating 317 an autosampler100 to automatically collect fluid sample that exits said flow cellafter the positive fluid quality stabilization status is identified 307.

In an example, the step of continuously pumping 303 is implementedand/or performed, at least in part, by a low-flow pump fluidly connectedor in fluid contact with a sample well. In the example, the sample wellis configured to monitor 319 contamination of ground water, includingoil or gas contamination, heavy metal contamination, solventcontamination, or contamination of a material from an industrialprocess.

Method 300 optionally further includes the step of auto-calibrating 321the fluid sensor before the measuring 305 step to ensure properfunctioning of sensors in the flow cell. In the example, theauto-calibrating 321 step includes flushing 323 the flow cell with cleanwater. The auto-calibrating 321 step also includes filling 325 the flowcell with a calibration solution. The auto-calibrating 321 step furtherincludes measuring 327 a calibration fluid quality parameter with thefluid sensor to ensure the sensor is calibrated, including over a rangeof calibration concentrations, to ensure accurate sensor readings beforeintroduction of fluid sample. The auto-calibrating 321 step furtherincludes calculating 329 a new calibration coefficient for the fluidsensor. The auto-calibrating 321 step also includes storing 331, inmemory device(s), the new calibration coefficient for a subsequent fluidtest measurement. The auto-calibrating 321 step further includesrepeating 333 (e.g., iterating) through the auto-calibrating 321 stepuntil all water quality parameters for all fluid sensors are calibrated.

In an example, the continuously pumping 303 step is automated orsemi-automated by measuring 335 fluid flow through said flow cell and/ormeasuring 337 a fluid depth in a sample well. In the example, themeasured 335 fluid flow and/or the measured 337 fluid depth generates339 an output that is provided 341 as an input to the low flow pump tocontrol pump power, thereby controlling 343 fluid flow in a feedbackloop so as to maintain 345 a substantially constant flow-rate and/orfluid depth in the sample well.

In an example, method 300 is implemented and/or performed, at least inpart, for simultaneous collection of low flow fluid samples from aplurality of wells with minimal active intervention by an operator.

EXAMPLE 2: GROUNDWATER SAMPLING SYSTEM

FIG. 5 is a method 402 for monitoring groundwater according to anembodiment of the disclosure. FIG. 6 is a schematic illustration of agroundwater sampling system 400 according to another embodiment of thedisclosure. In an example, method 402 is implemented and/or performed,at least in part, using the system 400 shown in FIG. 6. FIG. 7 is statediagram of a control scheme 510 for groundwater sampling. FIG. 8 is aprophetic example of a fluid stabilization condition, as determined by aturbidity sensor. Initially, as the pump is engaged and liquid is pumpedto the flow cell, there may be initially high turbidity, due tolong-term build-up prior to testing. The sensor(s) can be used toevaluate when a type of steady-state is achieved, indicating the fluidsample is “clean”, as determined by magnitude of deviation 930, such asa standard deviation or maximum deviation from an average over a certainnumber of fluid sample measurements or time period 932.

Referring to FIGS. 5 and 6, method 402 includes flowing 404, by at leastone pump 410, groundwater 535 under test from a groundwater source(e.g., a monitoring well 425) to at least one flow cell 430. Pump(s) 410include at least one pump controller 420. Flow cell(s) 430 includes oneor more fluid quality sensors 450. Method 402 includes, for an outputflow 459 of the groundwater 535 under test from the flow cell 430:collecting 406 a fluid sample 523 of the groundwater 535 under test; orcollecting 408 a waste fluid 470 in at least one waste container 460.Waste container(s) 460 include level sensor(s) 480. Method 402 includescontrolling 412, by a sampling controller 500, a groundwater monitoringsystem 400 used, at least in part, for implementing and/or performingmethod 402. Sampling controller 500 is communicatively coupled to pumpcontroller(s) 420, flow sensor(s) 440, and sensors 480 (in wastecontainer) and 530 (in well 429).

In method 402, the controlling 412 step includes receiving 414 signals520 from pump controller(s) 420, fluid quality sensor(s) 450, andsensors 480 and 530. The controlling step 412 also includes regulating416, based on the received signals 520, a flow-rate 423 to provide adesired or constant flow-rate to the flow cell 430. The controlling step412 further includes determining 418, based on the received signals 520,one or more fluid parameters over a time course. The controlling step412 also includes determining 422, based on the determined fluidparameter(s), a fluid stabilization status of groundwater 535 flowed tothe flow cell 430 from the pump 410. The controlling 412 step furtherincludes, in response to a fluid stabilization condition beingdetermined, initiating 424 collection (e.g., by the collecting 406 step)of at least one fluid sample 523. In an example, method 402 is performedas a continuous or semi-continuous process, and the controlling 412 stepis implemented for facilitating any or all of the aforementioned steps(e.g., flowing 404, collecting 406, and/or collecting 408 step(s)),and/or and any or all sub-steps thereof.

Referring to FIG. 6, system 400 includes a pump 410. In an example, pump410 is a low flow pump 410. Pump 410 includes a pump controller 420 forregulating a fluid flow-rate 423 from a monitoring well 425 through thepump 410. In an example, pump 410 is positioned on a ground surface 427,including proximal an opening 429 of monitoring well 425. In anotherexample (not shown in FIG. 6), pump 410 is positioned in the well 425below the ground surface 427. System 400 includes a flow cell 430 inflow communication with the pump 410, and a flow sensor 440. In theexample shown in FIG. 6, flow sensor 440 is positioned upstream of aninlet 433 of flow cell 430. In an example, flow sensor 440 iscommunicatively coupled to the pump controller 420 and/or a samplingcontroller 420. Flow cell 430 also includes one or more fluid qualitysensors 450. Exemplary fluid quality sensor(s) 450 include one or moreof: a turbidity sensor, a pressure sensor, a temperature sensor, adissolved oxygen (DO) sensor, an electrical conductivity sensor, a pHsensor, an electrochemical sensor such as an oxidation reductionpotential (ORP) sensor, and a fluorescence sensor. In an example, theflow cell 430 includes a plurality of fluid quality sensors 450 (e.g.,first 450 a, second 450 b, and third 450 c sensors). The sensor(s) 450may be incorporated into a multi-parameter sonde 535, with at least theactive sensing surfaces of the multi-parameter sonde 435 positioned inthe flow cell 430. In an example, flow cell 430 includes anauto-calibrator 455 for automatically calibrating the fluid qualitysensor(s) 450. System 400 includes a waste container 460 in flowcommunication with the flow cell 430 for collecting a waste fluid 470.In an example, waste container 460 is positioned on a ground pad 465,which providers a stable and protective weight bearing platform forcontainer 460. Pump 410 and/or pump controller 420 may also bepositioned on ground pad(s) 465 for similar purposes in system 400. Thewaste container 460 includes a level sensor 480 for measuring a wastefluid depth 490 in the waste container 460, including a pressure sensorto calculate fluid height in the container.

Referring to FIGS. 6 and 7, system 400 includes a sampling controller500 communicatively coupled to pump controller 420, flow sensor 440,fluid quality sensor(s) 450, and sensors 480 and 530. In an example,system 400 includes a communication device 501 communicatively coupledto sampling controller 500. In an example, communication device 501includes a telemetry system 503 positioned for and configured totransmitting and/or receiving data (e.g., encoded in sensor signals 520and/or system 400 control signals) to a mobile device 505 and/or aremote monitoring station 507.

Sampling controller 500 implements a control scheme 510 for system 400from a start state 501 (e.g., flow cell 430 awaiting flow of groundwater535 under test to inlet 433 of flow cell 430). In implementing controlscheme 510, sampling controller 500 receives 600 signals 520 from pumpcontroller 420, flow sensor 440, fluid quality sensor(s) 450, and levelsensor 480. In implementing control scheme 510, sampling controller 500transmits a control signal 537 to pump controller 420 to facilitateregulating 610 the fluid flow-rate 423 of groundwater 535 from the pump410 to the flow cell 430 based on the received signals 520 to provideand maintain a desired or constant flow-rate 423 to the flow cell 430.In an example, the desired or constant flow-rate 423 is greater than orequal to 1 mL/min and less than or equal to 500 mL/min (e.g., for a lowflow pump 410). In an example, sampling controller 500 regulates 610flow-rate 423 by implementing, including, without limitation, inconjunction with pump controller 420, proportional-integral (P.I.)feedback control 601.

In an example, flow-rate of groundwater 535 from pump 410 to flow cell430 may be determined by sampling controller 500 based on the signal(s)520 received from level 480 and/or depth 550 sensor(s) in the wastecontainer 460. For instance, for a waste container 460 having knowndimensions, a time rate of change in waste fluid 470 level and/or depthdetermined by sampling controller 500 is used thereby to determine theflow-rate, either instead of, or in addition to, based on the signal(s)520 received from flow sensor 440 and/or output flow sensor 457.

For implementing control scheme 510 (FIG. 7), sampling controller 500determines 613 waste fluid depth 490 in waste container 460 based onreceived signals 520 from a pressure transducer 550. In an example,sampling controller 500 provides 615 a waste fluid alarm 525 (e.g.,including, without limitation, an audible and/or a visual alarm) inresponse to the measured waste fluid depth 490 in the waste container460 being greater than or equal to a predetermined waste fluid depth 527(e.g., excess waste). In an example (not shown in FIG. 7), in responseto the determined 613 waste fluid depth 490 being greater than or equalto the predetermined waste fluid depth 527, sampling controller 500transmits control signal 537 to pump controller 420 to facilitatestopping operation of pump(s) 410 or decreasing flow-rate 423, therebyautomatically preventing waste overflow and attendant rick ofcontamination.

For implementing control scheme 510, sampling controller 500 determines620 one or more fluid parameters over a time course based on thereceived signals 520, including, without limitation, from fluid qualitysensor(s) (450). In implementing control scheme 510, sampling controller500 determines 630 a fluid stabilization status of groundwater flowed tothe flow cell 430 by the pump 410 based on the determined fluidparameter(s). In response to a fluid stabilization condition beingdetermined 630 (e.g., fluid stabilization achieved), sampling controller500 transmits a control signal 531 to flow cell 430 and/or to system 400components associated with and/or connected to flow cell 430 tofacilitate initiating 640 collection of at least one fluid sample 523 ofthe groundwater under test. In operation, all fluid (e.g., groundwater535) provided to flow cell 430 is either collected in the fluidsample(s) 523 or is directed to waste container 460 and collectedtherein as waste fluid 470.

Referring to FIG. 8, a plot 900 is a prophetic example of a fluidparameter (y-axis, e.g., turbidity of groundwater 535 under test)stabilizing over a time course (x-axis, e.g., hours). A turbidity dataset 910 generally decreases over the time course, with measuredturbidity values eventually dropping below a user-predetermined value920. In an example, for control scheme 510, sampling controller 500determines 630 that the fluid stabilization condition is achieved whenboth: a user-predetermined number (e.g., a number greater than 1) ofconsecutive measured turbidity values in the data set 910 have valuesless than or equal to the predetermined value 920; and those consecutivemeasured values have a standard deviation about a mean value of lessthan a user-predetermined standard deviation value 930 or a maximumdeviation from an average value over a certain number of sample valuesobtained over a time interval 932.

System 400 also includes a depth sensor 530 positioned in the monitoringwell 425 (e.g., at least partially submerged under groundwater 535surface 533). Depth sensor 530 is communicatively coupled to thesampling controller 500. In an example, for implementing control scheme510, sampling controller 500 assesses 650 a fluid draw-down level 540 inthe monitoring well 425 based on one or more signals 520 received fromthe depth sensor 530. In an example, sampling controller 500 provides670 a draw-down alarm 527 in response to the assessed 650 draw-downlevel 540 in the monitoring well 425 being greater than or equal to apredetermined draw-down level 549 (e.g., excess draw down). In anexample (not shown in FIG. 7), in response to the assessed 650 draw-downlevel 540 being greater than or equal to the predetermined draw-downlevel 549, sampling controller 500 transmits control signal 537 to pumpcontroller 420 to facilitate stopping operation of pump(s) 410 ordecreasing flow-rate 423.

System 400 further includes a pressure transducer 550 positioned at ornear (e.g., proximal) a bottom surface 560 inside of the waste container460 for measuring a depth of waste fluid 470 in the container 460.Pressure transducer 550 is communicatively coupled to the samplingcontroller 500. In an example, for implementing control scheme 510,sampling controller 500 determines 660 a waste fluid depth 470 in thewaste container 460 based on one or more signals 520 received from thelevel sensor 480. In an example, sampling controller 500 provides 615waste fluid alarm 525 in response to the determined 660 waste fluiddepth 470 in the waste container 460 being greater than or equal to apredetermined waste depth value 529 (e.g., excess level). In an example(not shown in FIG. 7), in response to the determined 660 waste fluiddepth 470 being greater than or equal to the predetermined waste depth529, sampling controller 500 transmits control signal 537 to pumpcontroller 420 to facilitate stopping operation of pump(s) 410 ordecreasing flow-rate 423.

System 400 may include a first valve 583 having a first valve controller585. In an example, first valve 583 is a first solenoid valve 583. Firstvalve controller 585 is operatively coupled to first valve 583 and iscommunicatively coupled to sampling controller 500. First valve 583 ispositioned upstream of the inlet 433 of flow cell 430. Under control offirst valve controller 585, first valve 583 enables flow 423 to bealternately directed to one or two flow paths: (A) to inlet 433 of flowcell 430; and (B) to waste container 460.

System 400 may include a second valve 587 having a second valvecontroller 589. In an example, second valve 583 is a second solenoidvalve 583. Second valve controller 589 is operatively coupled to secondvalve and is communicatively coupled to sampling controller 500. Secondvalve 587 is positioned downstream of an outlet 453 of flow cell 430.Under control of second valve controller 589, second valve 587 enablesoutlet flow 459 to be alternately directed to one or two flow paths: (C)to fluid sample collection 523; and (D) to waste container 460. Also,under control of second valve controller 589, second valve 587alternately opens and closes to facilitate alternately starting andstopping, respectively, flow of groundwater into or out of outlet 453.

System 400 may further include an outlet flow sensor 457. In the exampleshown in FIG. 6, outlet flow sensor 457 is positioned downstream ofoutlet 453 of flow cell 430. In the example, outlet flow sensor 457 ispositioned proximal outlet 453 of flow cell 430. Outlet flow sensor 457is communicatively coupled to the sampling controller 500. In anexample, for implementing control scheme 510, sampling controller 500compares 680, based on signals 520 received from flow sensor 440 andfrom outlet flow sensor 457, a first flow-rate (e.g., flow-rate 423)into the inlet 433 of flow cell 430 to a second flow-rate (e.g.,flow-rate 459) out of the outlet 453 of flow cell 430. In an example,sampling controller 500 subtracts a measured value of flow-rate 459 froma measured value of flow-rate 423. In the example, in response to amagnitude of a value of the difference between flow-rate 423 andflow-rate 459 being greater than or equal to a predetermined (e.g.,predetermined by a system 400 user) flow-rate difference value (e.g.,excess flow-rate difference), sampling controller 500 transmits 683 acontrol signal 539 to first valve controller 585 to facilitate diverting685, by first valve 583, the pumped flow of the groundwater 435 undertest from flow path A to flow path B. Diverting flow 423 from flow pathA to flow path B bypasses 687 flow cell 430. In an example, the value ofthe difference between flow-rate 423 and flow-rate 459 being greaterthan or equal to the predetermined flow-rate difference value isindicative of an operational problem in system 400 requiring attentionby user(s) thereof, such as an obstruction to fluid flow in the flowcell 430.

In an example, in response to the magnitude of the value of thedifference between flow-rate 423 and flow-rate 459 being greater than orequal to the predetermined flow-rate difference value, samplingcontroller 500 transmits 683 a control signal 553 to second valvecontroller 589 to facilitate closing second valve 587 and ceasing flow459 so that back flow (e.g., via flow path D) into the outlet 453 offlow cell 430 does not occur. In an example (not shown in FIG. 7), inresponse to the magnitude of a value of the difference between flow-rate423 and flow-rate 459 being greater than or equal to the predeterminedflow-rate difference value, sampling controller 500 transmits 683control signal 537 to pump controller 420 to facilitate stoppingoperation of pump(s) 410 or decreasing flow-rate 423. In an example (notshown in FIG. 7), in response to the magnitude of a value of thedifference between flow-rate 423 and flow-rate 459 being greater than orequal to the predetermined flow-rate difference value, samplingcontroller 500 provides a flow-rate alarm (e.g., including, withoutlimitation, an audible and/or a visual alarm).

For implementing control scheme 510, initiating 640 collection of fluidsample(s) 523 includes, in response to the fluid stabilization conditionbeing determined 630 (e.g., fluid stabilization achieved), samplingcontroller 500 transmits 690 a control signal 551 to second valvecontroller 589 to facilitate diverting 693, by second valve 587, thepumped flow (e.g., flow 459) of groundwater 435 under test from flowpath D to flow path C. This diverting 693 of flow 459 furtherfacilitates the collecting 406 step of method 402.

FIG. 9 is a schematic diagram of system 400 including an autosampler710. Referring to FIGS. 5-10, in an example, autosampler 710 includes anelectric motor 720. In an example, motor 720 is a stepper motor 720.Autosampler 710 includes a motor controller 730 coupled to motor 720.Motor controller 730 is communicatively coupled to sampling controller500. Autosampler 710 includes a sample platform 770 for holding aplurality of sample containers 780 (e.g., vials) for collecting andcontaining a plurality of fluid samples 523 (e.g., first 523 a, second523 b, . . . , (n-1)-th, and (n)-th samples 523), including, withoutlimitation, over the time course. To increment sample collection betweeneach of the plurality of containers 780, motor 720 incrementally movessample platform 770 (e.g., rotates in either a clockwise 760 orcounterclockwise direction about a center axis 750 by a predeterminedarc length 740).

In an example, upon sampling controller 500 initiating 650 collection offluid samples 523, groundwater 535 under test enters a first container780 via flow path C and is filled with first fluid sample 523 a.Sampling controller 500 facilitates flow of first sample 523 a into thefirst container 780 for a predetermined amount of time. Samplingcontroller 500 determines 695 the predetermined amount of time (e.g.,sample flow time) based on the flow-rate 459, the available volume offirst container 780, and the desired volume of first sample 523 a to becollected. Substantially simultaneously with the start of thepredetermined amount of time, sampling controller 500 facilitates, viasecond valve controller 489, diverting 693 flow 459 from flow path D toflow path C, thereby enabling collection of first fluid sample 523 ainto the first container 780. Substantially simultaneously with theconclusion of the predetermined amount of time, sampling controller 500facilitates, via second valve controller 489, diverting 697 flow 459from flow path C to flow path D, thereby stopping collection of firstfluid sample 523 a into the first container 780. Also, at or after theconclusion of the predetermined amount of time, sampling controller 500facilitates, via motor controller 730 receiving a motor control signal790 from controller 500, rotating 698 the sample 770 by thepredetermined arc length 740. Sampling controller 500 iterates 699through process steps associated with autosampler 710 for at least oneiteration, based on the number (n) of fluid samples 523 to be collected.

In any or all of the examples described above with reference to system400, system 400 components that transmit and/or receive data (e.g.,sensor signals 520 and/or system 400 control signals) may be wirelesslycommunicatively coupled to each other including, without limitation,using Bluetooth®, WiFi, Zigbee, and/or like wireless communicationprotocol(s) known to persons skilled in the art. In any or all of theexamples described above with reference to system 400, system 400components that transmit and/or receive data (e.g., sensor signals 520and/or system 400 control signals) may be communicatively coupled viawired connections including, without limitation, using serial, Ethernet,and/or like wired communication protocol(s) known to persons havingskill in the art. In any or all of the examples described above withreference to system 400, system 400 components that transmit and/orreceive data (e.g., sensor signals 520 and/or system 400 controlsignals) may be communicatively coupled to each other using both of, orcombinations of, wireless and wired communication protocols.

FIG. 10 is a schematic illustration of a networked computing environmentfor implementing the disclosed systems and methods for groundwater 535sampling. In an example, system 400 includes at least one computingdevice 810 communicatively coupled to one or more deployments of system400 (e.g., via telemetry system 503 of system 400 and a transceiver ofcomputing device 810, not shown in FIG. 10) in one or more deploymentlocations 815 (e.g., first 815 a, second 815 b, and third 815 cdeployment locations) through a network 805 (e.g., the Internet, anintranet, and/or a cellular network). Telemetry system 503 and/orcommunication device 501 transmits and receives data (e.g., sensorsignals 520 and/or system 400 control signals) to and from,respectively, the computing device (810). The computing device(s)include one or more of mobile device 505, remote monitoring station 507,a mobile smart phone 820, and at least one server 825.

In an example, system 400 is part of a multiplexed groundwatermonitoring system 800. Multiplexed system 800 includes a plurality ofgroundwater sampling systems 400 (e.g., first 400 a, second 400 b, andthird 400 c systems 400) for simultaneously monitoring of a plurality ofgroundwater sources (e.g., monitoring wells 425). Multiplexed system 800may be implemented and/or deployed over a geographic area of any size,including, without limitation, utilizing Internet of Things (IoT)protocols, standards, and practices.

Computing device(s) 810 include one or more processors 830communicatively coupled to one or more memory devices 840 (collectivelyreferred to herein as memory 840. Memory 840 stores including, withoutlimitation, by reading, writing, and/or deleting, data associated withoperation of system(s) 400. In an example, memory 840 includes anon-transitory computer readable medium 850 which stores processor830-executable instructions encoded as software 860 or firmware. Whenexecuted by the processor(s), the processor 830-executable instructionscause the processor(s) 830 to execute processor 830 and memory 840operations that facilitate implementing the control scheme 510 insystem(s) 400, as shown and described above with reference to FIGS. 5-9.In examples of system 400 and/or system 800 where computing device 810is a mobile smart phone 820, memory 840 thereof includes an app 870. Insuch embodiments, the app 870 includes the non-transitory computerreadable medium 850. In an example, computing device(s) 810 implementand/or perform, at least in part, the functionality of samplingcontroller(s) 420 in system(s) 400 and/or system 800, either instead of,or in addition to, sampling controller(s) 420 resident at or nearlocation(s) 815 of groundwater 535 source(s) (e.g., monitoring well(s)425).

In an example, system(s) 400 and/or multiplexed system 800 is/are usedin a groundwater 535 contamination monitoring and/or remediationapplication(s). In such embodiments, collected (e.g., in the collecting406 step of method 402) fluid sample(s) 523 is/are used for off-sitetesting of the fluid sample(s) 523. In an example, system(s) 400 and/ormultiplexed system 800 is/are used for monitoring and/or remediationapplication(s) for oil, gas, and/or chemical facilities and/or sourcesof actual or potential groundwater 535 contamination. In suchembodiments, where the above described components of system 400 arepositioned in proximity to flammable materials and/or chemicals, suchcomponent(s) are selected and/or installed in accordance with “explosionproof” standards so as to comply with application construction codesand/or related laws and regulations.

STATEMENTS REGARDING INCORPORATION BY REFERENCE AND VARIATIONS

All references throughout this application, for example patent documentsincluding issued or granted patents or equivalents; patent applicationpublications; and non-patent literature documents or other sourcematerial; are hereby incorporated by reference herein in theirentireties, as though individually incorporated by reference, to theextent each reference is at least partially not inconsistent with thedisclosure in this application (for example, a reference that ispartially inconsistent is incorporated by reference except for thepartially inconsistent portion of the reference).

The terms and expressions which have been employed herein are used asterms of description and not of limitation, and there is no intention inthe use of such terms and expressions of excluding any equivalents ofthe features shown and described or portions thereof, but it isrecognized that various modifications are possible within the scope ofthe invention claimed. Thus, it should be understood that although thepresent invention has been specifically disclosed by preferredembodiments, exemplary embodiments and optional features, modificationand variation of the concepts herein disclosed may be resorted to bythose skilled in the art, and that such modifications and variations areconsidered to be within the scope of this invention as defined by theappended claims. The specific embodiments provided herein are examplesof useful embodiments of the present invention and it will be apparentto one skilled in the art that the present invention may be carried outusing a large number of variations of the devices, device components,methods steps set forth in the present description. As will be obviousto one of skill in the art, methods and devices useful for the presentmethods can include a large number of optional composition andprocessing elements and steps.

When a group of substituents is disclosed herein, it is understood thatall individual members of that group and all subgroups, are disclosedseparately. When a Markush group or other grouping is used herein, allindividual members of the group and all combinations and subcombinationspossible of the group are intended to be individually included in thedisclosure.

Every formulation or combination of components described or exemplifiedherein can be used to practice the invention, unless otherwise stated.

Whenever a range is given in the specification, for example, atemperature range, a flow range, a number range, a time range, or acomposition or concentration range, all intermediate ranges andsubranges, as well as all individual values included in the ranges givenare intended to be included in the disclosure. It will be understoodthat any subranges or individual values in a range or subrange that areincluded in the description herein can be excluded from the claimsherein.

All patents and publications mentioned in the specification areindicative of the levels of skill of those skilled in the art to whichthe invention pertains. References cited herein are incorporated byreference herein in their entirety to indicate the state of the art asof their publication or filing date and it is intended that thisinformation can be employed herein, if needed, to exclude specificembodiments that are in the prior art.

As used herein, “comprising” is synonymous with “including,”“containing,” or “characterized by,” and is inclusive or open-ended anddoes not exclude additional, unrecited elements or method steps. As usedherein, “consisting of” excludes any element, step, or ingredient notspecified in the claim element. As used herein, “consisting essentiallyof” does not exclude materials or steps that do not materially affectthe basic and novel characteristics of the claim. In each instanceherein any of the terms “comprising”, “consisting essentially of” and“consisting of” may be replaced with either of the other two terms. Theinvention illustratively described herein suitably may be practiced inthe absence of any element or elements, limitation or limitations whichis not specifically disclosed herein.

All art-known functional equivalents, of any such materials and methodsare intended to be included in this invention. The terms and expressionswhich have been employed are used as terms of description and not oflimitation, and there is no intention that in the use of such terms andexpressions of excluding any equivalents of the features shown anddescribed or portions thereof, but it is recognized that variousmodifications are possible within the scope of the invention claimed.Thus, it should be understood that although the present invention hasbeen specifically disclosed by preferred embodiments and optionalfeatures, modification and variation of the concepts herein disclosedmay be resorted to by those skilled in the art, and that suchmodifications and variations are considered to be within the scope ofthis invention as defined by the appended claims.

1. A low flow groundwater fluid sampling system comprising: a low flowpump having a pump power; a flow cell in fluid communication with saidlow flow pump, wherein said flow cell comprises one or more fluidquality sensors; a flow sensor to control said pump power so as tomaintain a desired flow-rate through the flow cell; a communicationdevice in wireless communication with each of said low flow pump, flowcell and flow sensor, wherein: said low flow pump has an adjustable pumppower to provide a desired constant flow-rate to said flow cell from anelectronic communication between said low flow pump and said flowsensor, and said at least one fluid quality sensor measures one or morefluid parameters over a time course to assess a fluid stabilizationstatus; upon fluid stabilization said communication device indicates anaffirmative fluid stabilization condition and that a fluid sample may becollected.
 2. The system of claim 1, wherein said flow sensor comprisesa waste container and a level sensor operably connected to the wastecontainer, wherein the waste container is in fluid communication withsaid flow cell for collecting a waste fluid.
 3. The system of claim 1,further comprising a waste container in fluid communication with saidflow cell for collecting a waste fluid from said flow cell.
 4. Thesystem of claim 1, further comprising an autosampler in fluidcommunication with said flow cell, wherein an output flow from said flowcell for said affirmative fluid stabilization condition is directed tosaid autosampler for collection.
 5. (canceled)
 6. The system of claim 1,wherein said fluid quality sensors are selected from the groupconsisting of: a turbidity sensor, a pressure sensor, a temperaturesensor, an electrical conductivity sensor, a pH sensor, anelectrochemical sensor such as an oxidation reduction potential (ORP)sensor, a fluorescence sensor, and any combination thereof. 7.(canceled)
 8. The system of claim 1, wherein said flow cell furthercomprises an auto-calibrator for automatically calibrating said one ormore fluid quality sensors.
 9. The system of claim 1, wherein saiddesired or constant flow-rate is greater than or equal to 1 mL/min andless than or equal to 500 mL/min.
 10. The system of claim 2, whereinsaid waste container level sensor comprises a pressure transducer at abottom surface of said waste container to measure waste fluid level insaid waste container.
 11. The system of claim 1, wherein one or more ofa fluid flow-rate or a water well depth is transmitted to saidcommunication device and a control signal is transmitted from saidcommunication device to said low flow pump to maintain the desired orconstant fluid flow-rate and/or a water well depth.
 12. (canceled) 13.(canceled)
 14. The system of claim 1, wherein said communication devicecomprises a mobile smartphone.
 15. The system of claim 1, wherein saidcommunication device comprises a telemetry system positioned fortransmitting data to a mobile device or a remote monitoring station. 16.The system of claim 1 that is part of a multiplexed system comprising aplurality of said low flow groundwater sampling systems forsimultaneously monitoring of a plurality groundwater wells. 17.(canceled)
 18. (canceled)
 19. A method for collecting low flow fluidsamples from groundwater, the method comprising the steps of:continuously pumping a flow of groundwater fluid to a flow cell at asubstantially constant flow-rate; measuring a flow-rate through the flowcell and controlling a pump power based on the measured flow-rate so asto maintain the substantially constant flow-rate through the flow cell;measuring a fluid quality parameter time course with a fluid sensor insaid flow cell; identifying a positive fluid quality stabilizationstatus for said measured fluid quality parameter that reaches asteady-state value; and wirelessly transmitting a signal to acommunication device indicating a fluid sample is ready to be collectedfrom said flow of groundwater fluid.
 20. The method of claim 19, furthercomprising the step of manually collecting said fluid sample.
 21. Themethod of claim 19, wherein the measuring the flow rate comprises thesteps of: collecting a waste fluid that exits said flow cell in a wastecontainer; and monitoring a waste fluid level with a level sensorconnected to said waste container.
 22. The method of claim 21, furthercomprising the step of: activating an autosampler to automaticallycollect fluid sample that exits said flow cell after said positive fluidquality stabilization status is identified.
 23. The method of claim 19for simultaneous collection of a plurality of low flow fluid samplesfrom a plurality of wells.
 24. The method of claim 19, wherein saidcontinuously pumping is by a low-flow pump fluidly connected to a samplewell or in fluid contact with a sample well.
 25. The method of claim 24,wherein said sample well is configured to monitor contamination ofground water, including oil or gas contamination, heavy metalcontamination, solvent contamination, or contamination of a materialfrom an industrial process.
 26. The method of claim 19, furthercomprising the step of auto-calibrating said fluid sensor before saidmeasuring step by: flushing the flow cell with clean water; filling theflow cell with a calibration solution; measuring a calibration fluidquality parameter with the fluid sensor until stability is reached;calculating a new calibration coefficient for the fluid sensor; storingthe new calibration coefficient for a subsequent fluid test measurement;and repeating until all water quality parameters for all fluid sensorsare calibrated.
 27. The method of claim 19, further comprising measuringa fluid depth in a sample well, wherein the fluid depth generates anoutput that is provided as an input to said low flow pump to controlpump power, thereby controlling fluid depth in said sample well. 28-48.(canceled)